Thousands of Old Mines Pollute Colorado Waters, With No Help in Sight

Among the casualties: Peru Creek east of the Keystone ski area has been pronounced 'biologically dead.'

State environmental officials also have listed 32 sites along the Animas River in critical condition. Some headwaters of the Arkansas River, too, are 'virtually devoid of any aquatic life.'

The source of the contamination is abandoned mines — about 500,000 across the West, at least 7,300 in Colorado. Federal authorities estimate that the headwaters of 40 percent of Western rivers are tainted with toxic discharge from abandoned mines."